The investigator's long-term career objective is to become an independent clinician-scientist and educator in the fields of pediatric pharmacology, pharmacogenetics and pediatric hematology/oncology. This application involves formal didactic training in clinical research skills and a focused research proposal designed to form the foundation for a career in clinical research. Through participation in the Indiana University K30 program, the applicant will receive the didactic training necessary for a research career in clinical pharmacology. The candidate has the full support of the Chairman of Pediatrics and the Director of the GCRC and will perform her research in an outstanding clinical research environment. The proposed projects aim to determine which enzymes are involved in vinca alkaloid disposition and whether genetic polymorphisms in these enzymes and the membrane transporters that carry the vinca alkaloids are predictive of disposition, efficacy and toxicity. Despite the long history of vinca alkaloid use in oncology, the precise roles of the cytochrome P450 enzymes in their disposition remain largely uncharacterized. This is important because there is no definitive explanation for the significant variability in the pharmacokinetics of these drugs. As a result, pharmacokinetic or pharmacogenetic parameters that might predict vinca alkaloid toxicity and outcome have not been identified. The first aim of this proposal involves identification of the major metabolites of the vinca alkaloids, the enzymes involved in their production, and quantification of Michaelis Menten kinetic parameters for these enzymes. The second aim investigates the impact of pharmacogenetic polymorphisms in pertinent drug metabolizing enzymes and transporters on vinca alkaloid pharmacokinetics, toxicity, and efficacy in pediatric and adult cancer patients. Through these projects, this investigator will work toward her long-range research goal of understanding how genetic polymorphisms in drug metabolizing enzymes, receptors, and transporters influence the efficacy and toxicity of drugs in pediatric and adult cancer patients.